Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Spintronics / Magnetic Semiconductors / Transport

HL 91.12: Poster

Thursday, March 29, 2012, 16:00–19:00, Poster D

Interference in single quantum Hall point contacts — •Martin Treffkorn, Timo Hyart, and Bernd Rosenow — Institut für Theoretische Physik, Universität Leipzig, Germany

Recent experiments on quantum Hall interferometers have shown evidence of resistance oscillations that originate from partitioning a wave packet at a quantum point contact (QPC), letting the two partial waves propagate along different one-dimensional channels, and interfering them at a second QPC. A further miniaturization of devices is possible if one achieves interference within a single QPC. While this possibility is absent in a QPC modeled be a harmonic saddle point potential as suggested in [Phys. Rev. B, 1987, 36, 7969-7976], anharmonicities in the potential result in the appearance of backscattering paths in the open quantum system. These give rise to an interference area and explain the observed resistance oscillations [Phys. Rev. B, 1988, 38, 10162-10165]. In order to study resitance oscillations of a realistic QPC, we use a potential that is calculated self-consistently from the electrostatics of a semi-conductor heterostructure with top gates and numerically calculate the magnetoresistance of such a device.